1. Field of the Invention
The present invention relates to a terminal apparatus capable of suitably operating by transmitting at least video and audio data to hold a TV conference.
2. Description of the Related Art
An apparatus such as that shown in FIG. 1 is known as a conventional terminal of a TV conference system. As shown in FIG. 1, the terminal apparatus has a TV camera 10 for taking pictures of conference participants, a monitor 11 for displaying images of conference participants, materials used for conference and the like, a TV camera 12 for taking pictures of materials 14 such as drawings and originals on a material table 13, a video control section 15 for encoding and decoding video signals, a microphone 16, a speaker 17, an audio control section 18 for encoding and decoding audio signals, i.e., a signal supplied from the microphone 16 and a signal supplied to the speaker 17, a communication control section 19 for transmitting and receiving audio and video signals, an operating section 20 for operating the system, and a system control section 21 for control of the entire system.
A plurality of terminals each having this configuration are connected to each other through a communication circuit (not shown) such as a Local Area Network or a public telephone system and are used to hold a TV conference by transmitting and receiving video and audio signals.
FIG. 2 illustrates an example of a display on the monitor 11 when a TV conference is held. As illustrated, a picture 30 on the monitor 11 is formed of a conference room display window 31 in which a scene of a conference room in which another terminal is placed is displayed, a conference material display window 32 in which conference materials are displayed, a common board window 33 which is used for cooperative work and in which drawings, sentences or the like can be written from all conference rooms, and a personal work window 34 for doing personal work in each individual conference room.
In the conventional TV conference system arranged as described above, a picture of the entire conference room is taken by TV camera 10. Therefore, images of individual participants as displayed are so small that facial expressions of the speakers may be obscure. As a result, it is difficult for each of participants in a conference to grasp the ambiance of the conference.
FIG. 3 shows an example of another display on the monitor when a TV conference is held. A picture 35 on the monitor 11 in this example is generally the same as the above-described picture 30, but differs from the picture 30 in that the conference room display window 31 is replaced with a participant display window 36 for displaying conference participants at each of terminals connected through the communication circuit. Video images of the participants are always displayed in the participant display window 36.
In the example shown in FIG. 3, participants can grasp the ambiance of the conference. However, the amount of communication data exchanged between terminals is very large because information of a plurality of video images of conference participants is always being transmitted and received and the images displayed on the participant display window 36. Thus, the processing load imposed upon each terminal is large.
Also in the conventional TV conference system, audio signals input from microphones 16 are always transmitted and received. The amount of communication data between terminals is further increased thereby, so that the processing load upon each terminal is considerable. Further, even when no conference participants are speaking, any noise generated around each terminal is input through microphone 16 and transmitted to the other terminals. Such noise acts as a hindrance to the conference.